In the so called batch or barrel plating of metal parts, the parts to be plated are placed in a perforated barrel or basket carried on an overhead track system so as to move the parts from one station to the next. The stations comprise in a general way, a series of tanks containing pre-treatment, plating and post-treatment solutions. At each of the various stations, the barrel or basket of parts is lowered into a particular solution so that procedures such as cleaning, etching, removal of flashing, plating, rinsing and drying can take place.
Various problems exist with barrel plating operations of the kind referred to.
One problem is that in moving a barrel from one treatment station to another, it is next to impossible to control spillage of the treatment solution which drains from and drips off of the barrel as it is removed from the bath and transferred to the next station. In addition, since drainage is relatively slow, the entire process will be slow or else considerable contamination of one bath with the solution from a preceding bath occurs. Of special concern is the dilution of the electrolyte with solution from a preceding bath. In addition, because the barrel must move from one bath of solution to the next by means of a track, it is difficult and expensive to fashion hoods or covers for the baths and, consequently, evaporation of solution and the release of fumes into the atmosphere is difficult to control and is viewed as a significant environmental hazard. Still further, being essentially a batch operation, throughput of parts treated is relatively low. Difficulties in circulation of electroplating solution around the parts being plated exist, and high plating voltages must be used which not only means that the process is relatively inefficient but that anode life is relatively short.